Old Air Compressor

[lowpolyjoe]

So I've had this ~30gal craftsman air compressor for about 5 or 6 years.  I don't use it all that much so I was surprised when I started having problems with it lately. 

I would switch it on and nothing would happen.  If i toggled the switch a few times it would start up.  I thought the motor was starting to crap out.  After a while i couldn't get it to turn on at all.  I took the cover off the switch and discovered an internal metal piece had broken off and was loose inside the switch assembly - sometimes it would make contact, sometimes it wouldn't.   I took apart the switch itself today in hopes of soldering it back together.  It ain't gonna happen tho.   :D  Springs went flying everywhere when i opened it up and i still couldn't get access to where the broken piece attaches. 



The switch is about $55 on amazon (+shipping).   Ironically, there was also a recall on the compressor because the plastic shroud was too constrictive and caused overheating.  I ordered the recall parts quite a while ago and just got 4! boxes in the mail last week.  They sent me 4 refurb kits.   :D

I don't like this compressor because it's horizontal and takes up a ton of floor space.  It's also much bigger than i need.  I had been considering replacing it for a while.  So here's the question.

The motor is 2hp (6hp max?) unit.   I'm wondering if i scavenge this if it's a candidate for a bandsaw mill build.  Would a motor like this be capable of cutting anything?  Are there any problems using a "compressor motor" on a saw build?  I assume protection against dust is a big deal for any motor and i'd have to plan for that. 



The tank itself - maybe get a few bucks for it for scrap metal?

I could probably get a compressor that meets my needs (which are pretty small) for $100-$200 range and possibly start a bandsaw build.

What do you guys think? 

[sawguy21]

Two hp will run a carpentry shop band saw. That motor is also designed for intermittent duty, running it continuously would quickly overheat the windings. Don't throw it out, it will run all kinds of shop tools.

[beenthere]

What does this switch do in addition to turning power to the motor on/off ??

[sawguy21]

It is the pressure switch to shut the motor off at the maximum pressure and kick it back on when the minimum is reached. It also operates an unloader that releases pressure in the head on shut down to relieve starting load on the motor and breaker.

[Larry]

"Made in China" is a bad omen.  The specs on it are for a cheap motor.  The worst thing is the rpm.  Most bandsaws use a 17xx rpm motor to get the proper band speed.  You can do it with that motor but will need a big...8-10" machine pulley and a 2" or so motor pulley.  It will still be pushing light speed on the band.

Of course you may have a odd ball, or a bigger bandsaw where that faster motor might work out ok.  Most of the old 14" bandsaws run something like 2,500 to 3,200 fpm on the band.  Bigger bandsaws can run up to 4- 5,000 fpm.  You can do the calculations and see where your at. 

I would fix the switch and run it until it drops as a air compressor.

[caz]

I have one just like it bought it at an auction for $5.00 just the tank no motor.

I plumbed it to fill it up from my big compressor and use it with a hose,Its perfect for an air tank.

Change a wagon tire, fill up a tire what ever small job you need a little air for and it has wheels

[justallan1]

I'd fix it and use it, sell it cheap or give it to a friend or family member that could use it that can't afford one.

Allan

[Corley5]

I know a guy that spent a bunch of $$$ on a new pressure switch for a Coleman compressor before checking prices on new compressors.  He could have bought a whole new comparable machine for not much more than the cost of the switch.  It wasn't me either  ;D

[ancjr]

Fix/repair it as-is is good advice.  While you *could* make a bandsaw from it, it'd be a small "shop" sized bandsaw with 10, 12 or (pushing it) 14" bandwheels. 

[Al_Smith]

They grossly over rate some electric motors with words like"developes " etc .At 120 volt  and 15 amps it's probabley a true two HP but certainly not 6 and if so not for long before the magic smoke leaks out .

That pressure switch could have been replaced with just about any pressure switch FWIW .

I personally wouldn't get too excited about it .If it works use it .

[lowpolyjoe]

Thanks for the advice guys

Too bad the on/off switch includes all the pressure limit switching.  Would be nice just throw a light switch on there for $2
Sounds like the motor is not a great choice for a mill build and I'm not sure I'm up to it anyway.

Guess I'll fix it for ~$60 and then use it or maybe try to sell it and get a smaller one that suits

[moosehunter]

A word of caution about old compressors. A fellow that lived about a mile from my shop bought an older compressor from a yard sale or flea market, I don't remember which. He and a couple friends hooked it up in his basement garage and turned it on. After some time they got to thinking it should be up to pressure now and should have turned off. The owner walked over it to check the pressure and switch. It blew up just as he got close to it. Killed him instantly.
mh

[lowpolyjoe]

that's a terrifying story.  i  will only fix this with the correct stock replacement switch - no hacks here because of safety concerns as you mention. 

even if the pressure limiting switch was replaced with a regular switch, i would hope the air-release valve would blow out before the canister explodes.  but you never know.  and i surely don't want to find out the hard way.

you can save a lot of money buying things used, but i'm not a fan of used tools, especially power tools.  you never know what the previous owner did and how a hack will hold up over time.

[ancjr]

The tank can explode before the relief valve... but only if it has been abused... such as sitting for years with water in it, or it has been welded to modify or repair it without being retested under pressure.  Basically air tanks are like eating home canned food someone gives you.  If there's anything at all suspicious about it, don't risk it.